1. Field of the Invention
This invention relates to manually operated upright hand trucks with pivotally attached fulcrums and methods of use thereof to assist in getting the truck up a curb and onto a higher adjacent surface such as a sidewalk. More particularly, the present invention is a fulcrum providing arrangement on a hand truck, and a method of use thereof to allow the truck to be easily levered over the curb and onto the sidewalk with the truck handles being first to move over the curb.
2. Description of the Prior Art
This disclosure is teaching an invention applicable to the prior art type of manually operable hand truck which normally includes two rotatable wheels at the bottom end, the wheels being in spaced relationship and on oppositely disposed sides of a cargo platform also at the lower end, and with a wheel axle support extending between the two wheels, the axle being positioned just behind and slightly higher than the cargo platform. The cargo platform is located between the two wheels, and is generally horizontally disposed and resting on the ground when the truck is in the full upright or vertical non-moving or resting position. The cargo platform extends outward from the front of the truck, and the vertical center axis of the wheels is positioned sufficiently rearward of the cargo platform so that the wheels do not enter the cargo carrying area. Securely attached to the rearward portion of the cargo platform, and adjacent the wheel axle, are two vertically rising elongated side rails, normally between about 4 and 5 feet in length, which are in spaced relationship and normally parallel to one another. The rails extend upward generally perpendicularly to the cargo platform, and include hand grip areas or handles at the upper ends. The two rails are normally tied together with one or more transverse cross members for added strength and rigidity. The rails function to provide a back rest against which cargo on the cargo platform may lean or be tied, and additionally, the elongated rails serve as levers by which the single human operator of such a truck may tilt the cargo platform rearward at an angle, by pulling back on the rails, initially with one foot against the axle to brake the truck, to tilt the truck rearward, and to achieve balance of the load directly over the vertical center of the wheels to render the wheels as the only surface contacting portion of the hand truck. The operator may then maintain the weight balance using the leverage gained by the extended rails as he pushes, cargo platform first, the truck to his destination, with the truck tilted rearward with the hand grip areas normally positioned slightly above the waist height of the operator, and the rails tilted at about 35 to 45 degrees. The hereinabove described hand truck will henceforth be referred to as an "upright" type hand truck, since it is vertically upright when stationary, and tilted, but not horizontal when propelled along a surface by an operator. A few "upright" hand trucks include an additional set of spaced apart rotatably affixed wheels mounted upward toward the grip portion of the rails of the truck, with these two additional wheels serving to allow this particular truck design to also be used in a horizontally disposed position with four wheels contacting the ground at once when desired, however this type of four wheel truck is also designed for and is very usable in the "upright" position as described above, and therefore the present invention applies to both the two wheeled and four wheeled hand trucks of the "upright" nature.
Manually operated upright hand trucks for transporting cargo by a single operator have been used for many years to transport heavy or bulky loads such as refrigerators, heavy boxes and the like. One disadvantage with the use of such upright hand trucks is that heavily loaded trucks are not easily maneuvered up and over raised curbs and onto adjacent sidewalks. Typically, in attempting to maneuver a hand truck up over a curb, the operator generally ends up strenuously pulling the loaded truck up the edge of the curb, which can all too often result in injury to the operator's back or other body parts. Such awkward strenuous maneuvers can also lead to the displacement of the load.
To the best of my knowledge, all upright hand trucks presently in use are structured in a manner essentially requiring significant force and pulling or lifting to be applied by the operator in order to drag the truck up and over a curb, and this is leading to excessive numbers of back injuries and related insurance claims, not to mention increased fatigue and production slow downs.
Some prior art devices have attempted to address the problem of getting a hand truck up and over a curb or curb like obstacle by way of utilizing a pivotally attached fulcrum intermediate of the wheels and handles of the truck, yet, to the best of my knowledge, none are currently on the market for sale or in use. Some of these prior art devices are specifically structured for and described for use in getting the truck up stairs, while others are for the purpose of moving the truck up a curb onto an adjacent higher surface, such as a sidewalk for example.
The prior art devices of which I am aware, and feel are somewhat relevant to my invention are taught in U.S. Pat. No. 876,753 issued Jan. 14, 1908 to W. Wanee for "hand truck"; U.S. Pat. No. 1,334,726 issued Mar. 23, 1920 to P. M. White for "stair climbing hand truck"; U.S. Pat. No. 314,874 issued Mar. 13, 1908 to D. H. Rowe for "truck"; U.S. Pat. No. 217,864 issued Jul. 29, 1879 to T. Dolan for "wheelbarrow"; U.S. Pat. No. 3,175,835 issued Mar. 30, 1965 to P. J. Garrison for "dollie curb jumper"; U.S. Pat. No. 275,386 issued Apr. 10, 1883 to W. W. Hughes for "hand truck"; and U.S. Pat. No. 269,248 issued Dec. 1882 to J. W. Wetmore for a "stairway truck".
All of the above prior art devices involve the application of at least one pivotally attached extension downward below the rails for the purpose of serving as a fulcrum in conjunction with the rails for allowing leverage and the lifting of the cargo platform and adjacent wheels off of the ground temporarily, so as to be able to position the wheels upward onto an adjacent higher surface. Typical of all of these devices is that the fulcrum extension is pivotally attached to the rails so as to be able to change angle during use, with some of the devices having limits to the pivotal movement of the fulcrum while others do not. Also typical of many of these prior art devices is the use of a biasing arrangement, normally a spring to serve as a way of returning, automatically or semi-automatically the fulcrum extension to a given position after having pivoted to a second position during use. Another common feature of many of these prior art devices is the use of an extending rod or member secured to the pivotally mounted fulcrum at one end, with the opposite end of the extending member located up near the grip areas of the rails so as to allow the operator to pull or push the fulcrum into a given position while still being able to control the rails and thus truck during operation.
Another, and the most significant commonality of the prior art devices is the method of approaching the curb with the hand truck or truck-like device "wheels first", with the handle end of the rails positioned extending away or outward from the curb, and the fulcrum being placed on the lower surface for use in raising the wheels to the higher surface. As previously stated, I am not aware of any upright hand trucks for sale or in use anywhere at this time which utilize an affixed pivotal fulcrum to aid in moving the truck up a curb and onto a sidewalk or like raised surface, and I believe this situation to be due to the related prior art devices all being structured and geometrically arranged for the "wheels first" method of approach to the curb, as compared to the handles first approach of the present invention.
As exemplified in the Garrison and Wanee patents, the principles of the wheels first approach are that the truck is entirely on the lower surface, positioned with the wheels adjacent the curb, and the rails and handles extending outward away from the curb. The pivotal fulcrum is initially leaning toward the wheels as in Wanee, or vertical as in Garrison, and the distal end of the fulcrum is also on the lower surface below the raised surface. Then the operator pushes downward on the handles to pivot the truck about the pivots of the fulcrum in order to raise the wheels upward above the curb, at which time the operator pushes forward or allows forward movement (stops pulling rearward) on the handle to move the truck body forward, to cause or allow the distal end of the fulcrum to lean toward the handles, and for the front of the truck and wheels to move forward over the upper surface of the curb, followed by the operator raising the rails or continuing to push forward to lower the wheels onto the sidewalk or raised surface. With the wheels first approach, it can easily be envisioned that with common loads in the range of 150 or more pounds, the operator would have a difficult time in controlling the load balance simultaneously with the forward pushing or rearward pulling requirements, depending upon the starting position of the fulcrum and load weight distribution. If the process began with the fulcrum leaning toward the wheels as with Wanee, then horizontal pushing on the handles is required once the wheels are raised, wherein essentially the entire load (weight) of the truck and cargo is raised via tilting the fulcrum to more vertical without the assistance of gain provided by a lever to force the fulcrum up and over the top of its pivotal arc, or in other words, from leaning one direction to vertical, a more raised position, in order to pivot the fulcrum in the opposite direction and propel the truck forward over the top of the raised surface. If, the wheels first approach is started with the pivotal fulcrum vertical (90 degrees to the ground surface) as in the Garrison patent, then pulling rearward upon the handles while pushing down may be required of the operator, since, upon lifting the truck on the vertical fulcrum wherein the rails are tilted downward toward the ground at the lower wheel and cargo platform end, the Garrison truck will have a undesirable tendency to move forward. Depending upon the amount of weight and weight distribution on the truck, the operator may or may not be able to hold the Garrison truck from moving forward on the pivotal fulcrum toward the curb, and this problem will be particularly evident with heavy loading wherein most of the total weight is near the cargo platform, as opposed to being further up on the rails. With a heavy load, the Garrison truck may move forward wherein the cargo platform may abut the curb, rendering further vertical lifting difficult, since the cargo platform is the forward most portion of the truck, as is common with modern upright hand trucks.
So there is a significant need for improvement in getting a heavily loaded upright hand truck up a curb and onto an adjacent raised surface such as a sidewalk.
Furthermore, there are currently millions of upright hand trucks in use in the United States and around the world without any type of pivotal fulcrum thereon to assist in getting the truck over a curb, and since these trucks are relatively expensive, few owners thereof wish to dispose of their otherwise perfectly good hand trucks because of the problem of getting them up and over a curb, particularly when there are no feasible alternatives available on the market. Additionally, it should be noted that all of these hereinabove mentioned prior art devices appear reliant upon specifically located bolt holes, specifically placed notches and the like in the structural frame members, namely through the rails to allow the attachment of the fulcrum extensions, return springs and pull or push rods. Existing trucks are all structurally engineered and manufactured of materials of the desired known strengths and thicknesses to meet the designed load capacity of such trucks, and do not commonly have any holes in the rails which could be used to bolt on a pivotal fulcrum. To drill (cut) holes in the engineered structural members, particularly the rails which serve as levers and thereby are exposed to heavy loading, would tamper with the engineered structural integrity of the truck, possibly causing a structural member to fail under heavy loading which would be inconvenient in the very least, if not injurious to the operator or others near the truck at the time of the failure. Furthermore, there are many manufacturers of such upright hand trucks absent curb jumping fulcrums, and this has resulted in many slightly varying spacings between rails, and in location of reinforcement bracing normally placed from the lower portion of the rails downward to the wheel axle and to the rearward edge of the cargo platform to strengthen and tie these components together. In other words, there are no rigid standardizations of upright hand truck structures of this nature, although upright hand trucks made by numerous different companies all have substantial similarities to one another, since they operate on the same principles.
Therefore, there is a significant need for an improved structure and method for use on hand trucks for getting the truck up a curb and onto an adjacent raised surface such as a sidewalk, and such improvement would be ideal if it were applicable to upright hand trucks being currently manufactured, and also applicable to the millions of existing upright hand trucks.